The Human Stain
by Tw1 Spark1e
Summary: Smarty and Twilight are prince and princess after the coronation. But when a mysterious unicorn steals her crown, Twilight and Smarty have to follow the thief into a magic mirror to an alternate world to get it back. Will they get it back before it's too late? Take place during "Romance of Unicorn Hearts". Twilight x OC/Sunset x OC
1. Prologue

**A/N: Hello once again! I've decided to do this story alongside with Smarty's Hearth's Warming Eve story which is bound to be released late-November to early December. This story takes place during the first book "Romance of Unicorn Hearts". Now, I hope you all enjoy this, as it takes place in the Equestria Girls universe. You can decide if this is canon in the Smarty Heart universe or not, I'll have you make the decision. Now... onto the Prologue!**

* * *

Luna's moon shone high above in the sky with three of the brightest stars above it. It was sort of a special time of the year where the brightest stars near the Equis system would shine bright at their highest solar peak. It was the special event in which the stellar event was called "The Three Lunar Stars". The event would happen every thirty moons and has been happening since the thousand years when Nightmare Moon was banished to the moon.

Below the stars and moon, the Crystal Empire was at peace and the Crystal ponies were trotting through the streets of their peaceful empire. The latest news was heard all over Equestria as seen by a stand of newspapers. Twilight Sparkle, the student of Princess Celestia had become a princess herself. And she was coming to stay at the Crystal Palace where Princess Cadence, the ruler of the Crystal Empire was.

The train pulled by and out stepped the Princess of Magic with her children and the now-announced Prince Smarty that she was happily married to. Besides Smarty, her friends were there along with Spike and her little brother Theo with his friends Spark and Loki. They got off the train with everypony from the Empire bidding them welcome.

The princess and prince held onto their children Starlight and Dream Charmer when trotting through the city at sunset to arrive at the Crystal Palace. Pinkie Pie, Rarity, Rainbow Dash, Applejack and Fluttershy had never been happier with their two friends Twilight and Smarty now that they were of royalty.

"Hoo-wee! Your very first princess summit. You must be over the moon, Twilight." Applejack said to her lavender alicorn friend.

Twilight was excited to be a princess, but was feeling nervous about two things. But she was keeping Black Darkness aside to focus on what was happening at the moment since the Coronation. Twilight said "Oh, I am excited. But to be honest, I'm a little nervous too."

Pinkie Pie trotted over to her and said "You're nervicited! It's like you want to jump up and down and yell Yay Me! But you also want to curl up into a teeny-tiny ball and hide at the same time! We've all been there!" Fluttershy tapped Smarty's shoulder and he turned to look at his friend, as she quietly said "I'm there almost every day."

Applejack placed a hoof on her friend's shoulder and said "You've got no reason to fret Twi. Everything's going to be just-"

"TWILIGHT!" Rarity interrupted, noticing Twilight was missing something valuable. "Oh, I'm sorry darling… but I realized that you're not wearing your crown. You haven't forgotten it back in Ponyville, haven't you?"

Twilight turned to Spike and Theo and his friends who were guarding the bag and she said "It's in my bag. I just feel a little self-conscious about wearing it. Haven't really gotten accustomed to these wings yet either." She passed her daughter Dream Charmer to Pinkie, then lifted herself off the ground and tried to stay in the air for a couple of seconds, but fell flat on the ground.

Smarty took his princess' hoof and helped her off the ground. "Thanks Smarty." Twilight said, smiling at her husband. Smarty just smiled at her and said "No problem, my love." The flirt had caused Twilight to blush lightly, before she planted a gentle kiss on his lips.

Rarity approached Twilight once again and said "You are a princess now Twilight. Embrace it! I'm telling you, if I had a crown like that, I would never take it off. Why, I'd sleep in the thing." Twilight just smiled and held Smarty's hoof as she, him, their children and the rest of their friends trotted straighted into the Crystal Palace, ready to see what was in store.

* * *

The group entered the Crystal Palace's throne room, the very room where Smarty fought King Sombra and defeated him with the help of Twilight and the Crystal Heart. A royal guard blew into a horn to announce the arrival of Princess Twilight and Prince Smarty.

The purple and lavender alicorns trotted forward into the throne room, smiling when on the approach towards the three princesses. Along the way, Twilight bumped into one of the guards. An orange pegasus with gold guard armor. She quickly apologized and moved forward, putting her hoof around her prince.

The guard that Twilight bumped into cleared his throat and announced "Your Highness! Princess Twilight Sparkle and Prince Smarty Heart!"

Princess Cadence came trotting down towards the alicorns with the greeting smile on her face and said "Hello Twilight! Hello Smarty! I haven't seen both of you since the coronation, it's so good to see you!" Warp was there and he came galloping towards his buddy Smarty, giving him a warm welcoming hug. "Welcome Smarty." Warp said, smiling. The princess of the sun finally came down and looked at the new princess, her prince, her children and the rest of her friends.

"We have so much to discuss. But it can wait until tomorrow, you all look tired from your journey. Now off to bed, all of you." Princess Celestia said, smiling and proud to see Twilight and Smarty with their children and friends.

* * *

Twilight, Smarty and Spike finished putting their children into the cribs to have a good night's rest. Smarty began to work on the bed to set up for him and Twilight, and Spike was assisting Twilight to take out the things from her bag. Twilight took her crown from her bag using her magic and placed it upon her head. She took a look at her reflection in the mirror and softly sighed. Smarty looked up and trotted over to her.

"What's wrong, my love?" Smarty said, moving his gentle hoof to her and giving her soft and silky mane a calm stroke.

Twilight looked at Smarty and said "I don't know Smarty… I'm just worried. About both Black Darkness and how I'm a princess. Cadence was given the Crystal Empire to rule over, what if Celestia expects me to rule a kingdom of my own?"

Theo jumped over and shouted "That would… be awesome!"

"No it would not!" Twilight disagreed with her little brother. "Just because I have these crown and wings, it doesn't mean I'll be a good leader."

Smarty took her hoof and guided her to their bed, slipping into bed. Spike got onto his bed and said "Sure you will Twilight. Now you and Smarty should get some shut-eye. Big day tomorrow!" before he tucked himself in and went to sleep. Theo also left the room to go to sleep with his two other friends, Loki and Spark. Smarty then looked at Twilight and used his magic to place her crown off her and onto the nightstand.

Twilight gently began to cuddle with Smarty when she lay in bed with him. The prince and princess soon fell asleep together in bed, holding each other in love… until Twilight's wings sprung open. Twilight force-tucked her wings shut while she said "Just trying to get comfortable, wings!" When her wings closed, she closed her eyes and started to sleep…

…Her wings opened again and the sheets flew up, waking up Smarty wondering if Twilight was frustrated with her new wings that she just earned. Smarty just closed his eyes, knowing his sweetheart would get used to her new wings soon.

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_I don't own My Little Pony: Friendship is Magic or Equestria Girls! If I did, I wouldn't be writing this!__ The Smarty Heart, Starlight and Dream Charmer OCs are made by me while the Loki, Theo and Spark OCs were suggested by D.J. Scales._


	2. Thief In The Night

**A/N: Well, here it is. The next chapter to "The Human Stain". Also, in other news, I might make a FanFiction starring myself in it that has me go to Equestria, but I won't give spoilers what it will all be about. You'll just have to find out.**

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It was night-time in the Crystal Empire and everypony in the kingdom was snuggled into their beds, ready for a good night's rest. Twilight and her prince had already gone to bed, and the only ones awake were the guards. They were patrolling around the area to make sure nopony would disturb the sleeping ponies. Princess Luna was the only one awake and on the balcony, keeping an eye on her moon and watching it as she was born to do. She also kept an eye on the sleeping ponies below. Even with her being reverted back to normal, the memories of Nightmare Moon would always remain with her. But she knew how to control her own nightmares and keep the temptation of Nightmare Moon away from her.

Inside the Crystal Palace, there was a locked door down one hallway that remained untouched for a long time. The locks of the door finally flashed a white and then the sound of the doorknob turning was heard. The amber coated hoof came stepping forward from the opening door to make the entrance into the palace halls. However, the entire body of that pony wore a black cloak so nopony would be sure who it was. The pony looked through the hallways, making sure she knew where the prince and princess would be sleeping. After watching one guard pass by into another hallway, she made her move down in the hallway on the left towards the hallway where she would find the princess and prince.

The pony's shadow drifted across the long crystal hallway, silently moving like a shadow alongside the walls. At times, she would stop and hide behind a column as a shadow since guards were probably passing by. Once those guards passed by to another hall, the pony swiftly continued down the hallway. The shine of Twilight's crown was soon noticed by the pony and she trotted silently into the room that Twilight and Smarty were sleeping in.

Twilight was cuddled right next to Smarty in a form of hug when as the two alicorns slept. The cloaked pony trotted right up to their bed and watched them briefly sleeping together. The pony moved its amber hoof onto Smarty's cheek and gave it a stroke, and within that moment, the reflection of the nearby mirror shown that the pony was a female.

The pony soon turned to the crown and ignited a magic to reveal the pony to be a unicorn. The unicorn's magic was onto the crown when the unicorn was picking it up and placing it into the bag hidden below the cloak.

She then proceeded to the other bag on the opposite of where she put Twilight's crown. It was a fake version of Twilight's crown and she placed it right down onto the place where Twilight had her real crown there.

The unicorn then turned towards the door and quietly began sneaking back towards the room where she came out of. Little did she know though, was that Spike's tail was out and her hoof hit onto the tail, causing her to trip. The sound that came from the cloaked unicorn was "Uh." When she tripped and fell onto the tile.

The sound of the collapse caused Twilight and Smarty to wake up from their sleep. Smarty was rubbing his eyes awake and Twilight was yawning. When she turned to the sound of the collapse onto the tiles, she then noticed the unicorn thief, and with that… her real crown.

"MY CROWN!"

Twilight jumped right out of bed and grabbed Smarty by his hoof to get up out of bed. The cloaked pony got up and began to make her escape. Twilight ran faster than she ever did before with Smarty and everypony else making pursue towards the thief. "She's got my crown!" Twilight shouted during her pursue towards the unicorn thief. "Get her!" Smarty shouted, using a spell when gaining next to Twilight to teleport her and himself to the unicorn's path.

The unicorn was galloping head-on and kept galloping towards Smarty and Twilight when they teleported. "Stop!" Twilight shouted to the thief. There was a glow on the thief's horn and then a flash causing the cloak to go empty and move onto Twilight's face.

The unicorn appeared uncloaked when she teleported with the bags and the crown with her. It was an amber coated unicorn, with her mane being a vivid crimson and a brilliant yellow, and her eyes were the colour of cyan plus her cutie mark was a shimmering sun. She had that evil look on her face before turning forward and speeding off once again. "Don't worry Twilight. I'll go stop her!" Smarty shouted, speeding off towards the thief.

The thief turned her head during her gallop seeing that Smarty was in pursue. The alicorn opened his wings to gain speed towards the thief and watched a close eye. The thief was about to enter a room and at that surprise, Smarty swooped down and grabbed her, holding onto her. The thief didn't say anything, and was struggling to get free from Smarty. She then moved onto a wall and hit it, releasing the crown. Twilight entered at this point after getting the cloak off of her along with her friends.

The thief, Twilight, Smarty and the rest of the elements watched the crown released, and reflecting off the walls, before heading into the mirror. Twilight then galloped to the thief and said "What did you do to my crown?!" The unicorn just kept a smile with a mean glare towards Twilight.

"Sorry it had to be this way… Princess and Prince."

The unicorn then teleported to the mirror and left one last smile with a glare that told them that she beat them, before jumping into the mirror and disappearing entirely, leaving the group wondering what she did with her crown. "Who... who was that?" Fluttershy asked, wondering who that was.

* * *

"Sunset Shimmer." Princess Celestia said, looking down at the group from the throne room. It was the next morning and after Twilight's crown was stolen. "A former student of mine. She began her studies not long before Twilight. But when she did not get what she wanted as quickly as she liked, she turned cruel and dishonest. I tried to help her, but she eventually decided to abandon her studies and pursue her own path. One that has sadly led to her stealing your crown."

Spike held out the fake version of Twilight's crown. He said "She replaced Twilight's crown with this lookalike."

"I suppose Sunset Shimmer thought you wouldn't notice right away that this was not yours. And by the time you did, it would be too late to go after your crown and element of harmony." Princess Celestia said, looking at the fake crown.

Twilight stepped forward from next to Smarty and said "But I don't understand. Where did she go? Why did she take the crown?"

Princess Celestia just looked down at her and said "You'll soon know more about this place than I do."

* * *

In the room with the magic mirror, Princess Luna looked at it to her own reflection. "This is no ordinary mirror. It is a gateway to another world. A gateway that opens once every thirty moons."

Pinkie Pie's hoof went right onto the mirror, causing it to shine. "Sparkly!" The pink earth pony commented as she moved her hoof around the portal. Princess Luna just used her magic to grab Pinkie's hoof as she rolled her eyes and moved Pinkie back to the group.

"It has always been kept in the throne room of Canterlot Castle. But when Princess Cadence took over the Crystal Empire, we sent it here for her to watch over." Princess Luna continued, seeing the curious looks on the faces of the elements.

Princess Celestia sighed behind Twilight and said "I had always hoped that Sunset Shimmer would someday use it to return, to come back to Equestria seeking my guidance. Obviously, this is not what has happened."

"Twilight, you must use the mirror to go into this other world and retrieve your crown. Without it, the other Elements of Harmony have no power and Equestria is left without one of its most important means of defense, even if it's Black Darkness." Princess Cadence said, using her magic to place two bags around Twilight.

Princess Luna stepped away from the mirror and said "Your crown does not belong in the place Sunset Shimmer now calls home. And in her possession, your Element of Harmony will no doubt be used to inflict harm onto the inhabitants of this other world. They will not have the power to defend themselves."

"You understand the importance of your task?" Princess Celestia asked Twilight, looking down at the Princess of Magic.

"Of course." Twilight said, with a brave tone.

"Good, then you must go at once." Princess Celestia said, placing her hoof onto Twilight's shoulder. Twilight finally sighed and moved forward towards the mirror. But halfway to the mirror, Rainbow Dash stops in front of her.

"Whoa whoa whoa… if Twilight is going… all of us are going!" Rainbow Dash said, standing tall with the rest of the elements, and Theo, Spark and Loki by their side.

"I'm so nervicited!" Pinkie Pie said, sounding really excited to enter the other world. Applejack just tapped her on the shoulder and said "You do realize that's not a real word, right?"

Theo jumped up and down saying "I'm going in there with my sister, even if it means putting myself in danger. But I know how to defend myself just I helped fight King Sombra's guards." Loki and Spark nodded in a complete agreement.

Princess Celestia just closed her eyes and said "I'm afraid I can't let any of you go."

"WHAT?! Why not?!" Rainbow Dash said, disappointed with the tone of voice.

"Sending all of you could upset the balance of this alternate world, creating havoc that would make it impossible for Twilight to get the crown back from Sunset Shimmer. This is something Princess Twilight must do alone." Princess Celestia explained, trying to defend the alternate world as well.

Princess Luna placed a hoof onto Twilight's shoulder and said "Time is of the essence. On the third day when the moon reaches its peak in the night sky, the gateway will close. And it will be another thirty moons before you will be able to use it to return."

Twilight then stepped up toward the mirror and she turned around to see her prince, Smarty approaching her. "Please be safe Twilight." Smarty said, giving her soft and silky mane one last stroke.

"I will, Smarty. When did I ever get hurt?" Twilight said, holding him close. The two finally shared a romantic kiss and let go, with Smarty saying "I love you."

Twilight smiled back and said "I love you too Smarty." And watched Smarty move backwards to the group. She then turned forward to the mirror and placed her hoof onto it. The mirror went bright, and then she moved forward into the gateway, disappearing through the mirror.

Spike at this point was nervous about Twilight's safety and hopped right onto Smarty's back and pulled back Smarty's mane causing him to move forward. "Hi-ho Smarty! Away!" Spike said, seeing Smarty move towards the portal with him on top.

"Spike! Smarty! NO!" The elements called out, but it was far too late for Smarty to stop. He went right into the portal with Twilight and Spike. The portal spun them through circles like a twister as they saw white first… and then it all went black.

* * *

"Uhhh…" Twilight groaned, regaining consciousness from the portal. Once her vision cleared, she could see the ground below her. She then looked up at the grass that was there.

"Uh, Twilight?" Spike said, out of her sight.

Twilight regained full conscious and turned to Spike, saying "Spike, you're not supposed to- Wait… Spike? Are you a dog?"

Spike was transformed into a dog, and he said "I… think so. But I have no idea what you and Smarty are."

Twilight turned to her prince. He looked completely different and his hooves were different. He nervously said "You… you look absolutely fine Twilight." And had a guilty face on him, he looked like a gentlemen and looked rather curious too.

"Huh?" Twilight said, finally she decided to look at her hooves, but they were not hooves at all. They were completely different. She then looked at the sky of the alternate world and began to scream.

* * *

_I don't own My Little Pony: Friendship is Magic! If I did, I wouldn't be writing this, now would I?_


End file.
